- Allyl Isopropenyl Dicarbonate; A Convenient Reagent for the Preparation of Allyl Esters of Carboxylic Acids
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Allyl isopropenyl dicarbonate(1) reacts with carboxylic acids in the presence of 4-dimethylaminopyridine(DMAP) catalyst to give allyl esters in high yields under mild conditions such as in a near-neutral medium at room temperature.
- Takeda, Kazuyoshi,Akiyama, Akira,Konda, Yaeko,Takayanagi, Hiroaki,Harigaya, Yoshihiro
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- Triazine-Based Cationic Leaving Group: Synergistic Driving Forces for Rapid Formation of Carbocation Species
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A new triazine-based cationic leaving group has been developed for the acid-catalyzed alkylation of O- and C-nucleophiles. There are two synergistic driving forces, namely, stable C=O bond formation and charge-charge repulsive effects, involved in the rapid generation of the carbocation species in the presence of trifluoromethanesulfonic acid (～200 mol %). Considerable rate acceleration of benzylation, allylation, and p-nitrobenzylation was observed as compared to the reactions with less than 100 mol % of the acid catalyst. The triazine-based leaving group showed superior p-nitrobenzylation yield and stability in comparison to common leaving groups, trichloroacetimidate and bromide. A plausible reaction mechanism (the cationic leaving group pathway) was proposed on the basis of mechanistic and kinetic studies, NMR experiments, and calculations.
- Fujita, Hikaru,Kakuyama, Satoshi,Fukuyoshi, Shuichi,Hayakawa, Naoko,Oda, Akifumi,Kunishima, Munetaka
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p. 4568 - 4580
(2018/04/26)
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- Trimethylphosphine-Promoted Alcoholysis of α,β-Unsaturated Imides and α,β-Unsaturated Esters
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α,β-Unsaturated imides and α,β-unsaturated esters were found to undergo alcoholysis in the presence of trimethylphosphine. The reaction is initiated by nucleophilic addition of trimethylphosphine to the double bond of the α,β-unsaturated carbonyl compound. Saturated imides also undergo the alcoholysis in the presence of the corresponding α,β-unsaturated imide.
- Sato, Haruka,Hosokawa, Seijiro
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p. 1343 - 1349
(2018/01/27)
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- In situ synthesis of 2-allyloxy-1-methylpyridinium triflate for the allylation of carboxylic acids
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2-Allyloxypyridinium triflate is formed in situ by treating a mixture of 2-allyloxypyridine, a carboxylic acid, and toluene with methyl triflate. Subsequent warming of the reaction mixture in the presence of potassium carbonate leads to efficient formation of allyl esters in good to excellent yields.
- Strayer, Timothy A.,Culy, Caleb C.,Bunner, Matthew H.,Frank, Amie R.,Albiniak, Philip A.
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supporting information
p. 6807 - 6809
(2016/01/26)
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- Synthesis of l -octaarginine through microencapsulated palladium-catalyzed allyl ester deprotection
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Octaarginine has been described as a molecular transporter. We report a useful synthesis of orthogonally protected l-octaarginine by using a method based on a microencapsulated palladium catalyst. Known palladium-based methods for allyl ester deprotection have been modified to facilitate purification of the unprotected intermediates. This improvement in the purification step has also been tested with a variety of allyl α-amino esters and allyl α,β-unsaturated esters.
- Pérez-López, Ana M.,González-Calderón, Dávir,Occorso, Antonio,Galindo-ángel, Javier,Domínguez-Seglar, José F.,Tamayo, Juan A.,Díaz-Gavilán, Mónica,Gómez-Vidal, José A.
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supporting information
p. 2319 - 2322
(2015/08/06)
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- Nucleophilic carbene-catalyzed redox-esterification reaction of α-halo-α,β-unsaturated aldehyde
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A nucleophilic carbene catalyzed redox esterification between α-halo-α,β-unsaturated aldehydes and various alcohols has been developed. Interestingly, the reaction provided α,β-unsaturated esters instead of the saturated α-halo substituted esters as the only product in good to high yield with excellent trans-selectivity, presumably via the umpolung-halo-elimination pathway.
- Wang, Xiang-Bo,Zou, Xiao-Lei,Du, Guang-Fen,Liu, Zhi-Yong,Dai, Bin
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p. 6498 - 6503
(2012/08/27)
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- Palladium-catalyzed divergent reactions of α-diazocarbonyl compounds with allylic esters: Construction of quaternary carbon centers
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Take two: α-Diazocarbonyl compounds display a diverse pattern of reactivity upon palladium-catalyzed reaction with esters. Esters bearing an alkynyl group on the carbonyl carbon atom lead to two different C-C bonds at the same carbon atom in a single operation through decarboxylation and migratory insertion, whereas aromatic and benzylic acid derivatives afford aromatic and benzylic esters bearing an O-substituted quaternary carbon center. Copyright
- Chen, Zi-Sheng,Duan, Xin-Hua,Zhou, Ping-Xin,Ali, Shaukat,Luo, Jian-Yi,Liang, Yong-Min
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supporting information; experimental part
p. 1370 - 1374
(2012/03/27)
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- [Pd(μ-Br)(PtBu3)]2 as a highly active isomerization catalyst: Synthesis of enol esters from allylic esters
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The dimeric Pd(I)-complex [Pd(μ-Br)(PtBu3)] 2 was found to be highly active for catalyzing double-bond migration in various substrates such as unsaturated ethers, alcohols, amides, and arenes, under mild conditions. It efficiently mediates the conversion of allylic esters into enol esters, rather than inserting into the allylic C-O bond. The broad applicability of this reaction was demonstrated with the synthesis of 22 functionalized enol esters.
- Mamone, Patrizia,Gruenberg, Matthias F.,Fromm, Andreas,Khan, Bilal A.,Goossen, Lukas J.
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supporting information; experimental part
p. 3716 - 3719
(2012/09/08)
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- Irreversible catalytic ester hydrolysis of allyl esters to give acids and aldehydes by homogeneous ruthenium and ruthenium/palladium dual catalyst systems
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An irreversible hydrolysis reaction of allyl esters (1) into carboxylic acids (2) and propanal (3) was achieved with a ruthenium/palladium (Ru/Pd) dual catalyst system. The optimized catalysts consists of a 1:1:1 mixture of (cyclopentadienyl)tris(acetonitrile)ruthenium hexafluorophosphate {[RuCp(MeCN)3] PF6}, bis(acetonitrile)palladium dichloride [PdCl2(MeCN)2] and 1,6-bis(diphenylphosphanyl)hexane (DPPHex). The reaction proceeds via isomerization of allyl esters to 1-propenyl esters and hydrolysis of them to give 2 and 3. The first isomerization step was virtually catalyzed by the Ru components and the second hydrolysis step was mainly catalyzed by the Pd components. The optimized bidentate phosphine (DPPHex) which has long alkylene chain effectively generates two vacant sites on the Ru centers by bridging coordination. When a chelating bidentate phosphine such as DPPE was employed, only one vacant site remained on the Ru center and resulted in a low activity. This chelating Ru complex of DPPE formed even in the presence of 2 equivalents of Ru or additional 1 equivalent of Pd. These differences in coordination behaviour between DPPHex and 1,2- bis(diphenylphosphanyl)ethane (DPPE) cause the differences of the catalytic activity in the first step. The phosphine coordination to Pd center slightly decreases the activity of second hydrolysis step but which was compensated by the increasing of the stability of Pd. On the whole, the optimized Ru/Pd dual catalyst system exhibited good performances on the irreversible hydrolysis of allyl esters.
- Nakamura, Asami,Hamasaki, Akiyuki,Goto, Sachihiko,Utsunomiya, Masaru,Tokunaga, Makoto
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supporting information; experimental part
p. 973 - 984
(2011/06/19)
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- N-heterocyclic carbene-mediated oxidative esterification of aldehydes: Ester formation and mechanistic studies
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An unexpected N-heterocyclic carbene-catalyzed esterification of α,β-unsaturated aldehydes including aromatic aldehydes with reactive cinnamyl bromides in the presence of air oxygen or MnO2 as an oxidant is described. In the presence of oxygen, halogenated and electron-deficient aldehydes react smoothly to furnish esters in good yields. Great efforts have been made on mechanistic studies to deduce a plausible mechanism, based on the experimental results and isotopic labeling experiment.
- Maji, Biswajit,Vedachalan, Seenuvasan,Ge, Xin,Cai, Shuting,Liu, Xue-Wei
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experimental part
p. 3016 - 3023
(2011/06/20)
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- Nucleophilic iron catalysis in transesterifications: Scope and limitations
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Figure presented The ester bond is one of the most common structural motifs found in nature. Apart from the condensation between an acid and an alcohol, transesterifications represent another mechanistic alternative for the preparation of this compound class. The present paper summarizes our most recent investigations in this field, using nucleophilic iron complexes as catalysts for transesterifications under neutral conditions. This new type of metal catalyst complements the existing methodologies, which rely on Lewis acidic metal complexes. Investigations on scope and limitations, stereochemical course, and chemoselectivities will be presented.
- Magens, Silja,Plietker, Bernd
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supporting information; experimental part
p. 3715 - 3721
(2010/08/07)
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- Microwave-assisted ester formation using O-alkylisoureas: A convenient method for the synthesis of esters with inversion of configuration
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(Chemical Equation Presented) The formation of carboxylic esters via reaction of carboxylic acids with O-alkylisoureas proceeds in excellent yields with very short reaction times when conducted in a monomode microwave synthesizer. Efficient processes were
- Chighine, Alessandra,Crosignani, Stefano,Arnal, Marie-Claire,Bradley, Mark,Linclau, Bruno
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experimental part
p. 4753 - 4762
(2009/10/17)
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- A tandem Finkelstein-rearrangement-elimination reaction: a straightforward synthetic route to allyl esters
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Allyl esters can be obtained by a Finkelstein-rearrangement-elimination reaction of 2-chloro-1-(chloromethyl)ethyl esters induced by NaI. Sodium iodide can be used below equivalence using a reductive agent as sodium thiosulfate. High yields are obtained with most of the diverse esters studied. The method described avoids the use of allyl alcohol as a reagent. 2-Chloro-1-(chloromethyl)ethyl esters are prepared from glycerol, the main by-product of biodiesel industry. The effectiveness of iodine as reagent to hydrolyze allyl esters is also confirmed.
- Eras, Jordi,Escribà, Marc,Villorbina, Gemma,Oromí-Farrús, Mireia,Balcells, Mercè,Canela, Ramon
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experimental part
p. 4866 - 4870
(2009/10/02)
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- Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols
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(Chemical Equation Presented) A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO4-SiO2). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C10) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H2SO4, HBr, TfOH, HBF4, and TFA that were adsorbed on silica gel were less effective compared to HClO4-SiO2 following the order HClO4-SiO 2 ? H2SO4-SiO2 > HBr-SiO 2 > TfOH-SiO2 ? HBF4-SiO2 ≈ TFA-SiO2. When HClO4 was immobilized on other solid supports the catalytic efficiency followed the order HClO4-SiO 2 > HClO4-K10 > HClO4-Al 2O3 (neutral) > HClO4-Al2O 3 (acidic) > HClO4-Al2O3 (basic).
- Chakraborti, Asit K.,Singh, Bavneet,Chankeshwara, Sunay V.,Patel, Alpesh R.
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supporting information; experimental part
p. 5967 - 5974
(2009/12/24)
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- Enzymatic removal of carboxyl protecting groups. III. Fast removal of allyl and chloroethyl esters by Bacillus subtilis esterase (BS2)
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(Chemical Equation Presented) An esterase from Bacillus subtilis (BS2) allows the fast and selective removal of allyl, 2-chloroethyl, and 2,2,2-chloroethyl esters under mild conditions in high yields. In addition, BS2 easily hydrolyzes phenacyl esters, while the hydrolysis of sterically hindered diphenylmethyl esters is slow, requiring longer reaction time and higher enzyme/substrate ratio.
- Fotakopoulou, Irene,Barbayianni, Efrosini,Constantinou-Kokotou, Violetta,Bornscheuer, Uwe T.,Kokotos, George
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p. 782 - 786
(2007/10/03)
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- Polymer-supported O-alkylisoureas: Useful reagents for the O-alkylation of carboxylic acids
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Polymer-supported O-alkylisoureas were prepared by reaction of an alcohol with a polymer-supported carbodiimide under copper(II) catalysis. These reagents were used to transform carboxylic acids into the corresponding methyl, benzyl, allyl, and p-nitrobenzyl esters in a highly chemoselective manner in high yields and in very high purity after simple resin filtration and solvent evaporation. The reactions could be carried out using both conventional or microwave heating, with reaction times as short as 3-5 min in the latter case, without compromising yield, purity, or chemoselectivity. Unfortunately, the corresponding solid-supported tert-butyl isoureas could not be prepared.
- Crosignani, Stefano,White, Peter D.,Linclau, Bruno
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p. 5897 - 5905
(2007/10/03)
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- Polymer-supported O-benzyl and O-allylisoureas: Convenient preparation and use in ester synthesis from carboxylic acids
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Polymer-supported O-methyl, O-benzyl, and O-allyl-isoureas were prepared by copper(II)-catalyzed reaction of polymer-supported carbodiimide with the corresponding alcohols. These polymer-supported reagents were successfully employed to convert a series of carboxylic acids to methyl, benzyl, or allyl esters, in good yields. The products were obtained with high purity (>95% by NMR) after a simple resin filtration-solvent evaporation sequence.
- Crosignani, Stefano,White, Peter D.,Steinauer, Rene,Linclau, Bruno
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p. 853 - 856
(2007/10/03)
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- Novel alkylation, lactonisation and cascade coupling processes mediated by lead tetracarboxylates: The importance of ligands
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The reactions of lead(IV) tetracarboxylates with carboxylic acids containing unsaturated side chains is reported. At elevated temperature in toluene, facile decarboxylation or lactonisation processes are observed, depending on the length of the carboxylat
- Moloney, Mark G,Nettleton, Ewan,Smithies, Kirsty
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p. 907 - 909
(2007/10/03)
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- Convenient synthesis of benzyl and allyl esters using benzyl and allyl 2,2,2-trichloro-acetimidate
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Benzyl and allyl 2,2,2-trichloroacetimidate are efficient reagents for the preparation of benzyl and allyl esters of carboxylic acids in the presence of a catalytic amount of boron trifluoride-diethyl ether complex.
- Kokotos, George,Chiou, Antonia
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p. 168 - 170
(2007/10/03)
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- THE SYNTHESIS, CHARACTERISATION AND REACTIVITY OF SOME LEAD(IV) CARBOXYLATES
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A detailed examination of the preparation, characterisation and reactivity of a range of lead(IV) carboxylates is reported.The replacement of the acetate ligands of lead(IV) tetraacetate by other carboxylates gives the lead(IV) tetracarboxylates 1-16, which have usually been found to be more stable than lead tetraacetate with respect to hydrolysis.These compounds react with allyltributylstannane to give high yields of the corresponding allyl esters 20-34 under mild conditions.
- Buston, Jonathan E. H.,Coop, Andrew,Keady, Richard,Moloney, Mark G.,Thompson, Russell M.
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p. 1101 - 1116
(2007/10/02)
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- Dicarbonates: Convenient 4-dimethylaminopyridine catalyzed esterification reagents
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The DMAP (4-dimethylaminopyridine) catalyzed reaction of dialkyl dicarbonates la-e and carboxylic acids 2 afforded the corresponding esters 5 in good yield.
- Takeda,Akiyama,Nakamura,Takizawa,Mizuno,Takayanagi,Harigaya
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p. 1063 - 1066
(2007/10/02)
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- REACTIONS DE WITTIG-HORNER ET DE TRANSESTERIFICATION EN UNE OPERATION PAR ACTIVATION ANIONIQUE DE LIAISONS C-H ET O-H EN MILIEU HETEROGENE CARBONATE DE POTASSIUM/ALCOOL
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The Wittig-Horner reaction carried out in various alcohols is accompanied by transesterification of the alkyl radical of the α,β-ethylenic ester formed.The occurrence of these two reactions in the same reaction medium is affected by the behavior of: i) the alcohol (solvent and reagent), ii) potassium carbonate (reagent and catalyst).The propensity for the two reactions to occur was found to depend on the polarity of the alcohol.Protic alcohols speeded both the Wittig-Horner and the subsequent transesterification reaction.Both reactions were quantitative despite the use of non-stoichiometric amounts of potassium carbonate.Regeneration in situ of the solid base observed in aprotic medium was markedly enhanced under these reaction conditions.The mechanism proposed for these two reactions incorporates this regeneration process.
- Mouloungui, Z.,Elmestour, R.,Delmas, M.,Gaset, A.
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p. 1219 - 1232
(2007/10/02)
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- THE STUDIES OF CARBENOID REACTIONS OF α-O-ALLYL- or α-N-ALLYL-α'-DIAZOPROPANONE DERIVATIVES CATALYZED BY VARIOUS METAL IONS
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Both cupric acetylacetonate and palladium(II) acetate are good catalysts to induce the carbon-carbon double bond addition reaction for α-O-allyl- or α-N-allyl-α'-diazopropanone derivatives.The heteroatom did not play an important role in enhancing the carbon-hydrogen bond insertion for compound (3).
- Hon, Yung-Son,Chang, Rong-Chi
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p. 1089 - 1099
(2007/10/02)
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- The effects of the carbonyl group in the cyclization of 1-hexenyl radicals
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The radical chain cyclization of allyl ether derivatives promoted by tosyl halides and light is suppressed by the presence of one carbonyl group conjugated with the double bond (acrylic double bond).
- Serra,Da Silva Correa,Do Vale
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p. 9463 - 9488
(2007/10/02)
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- DI-2-PYRIDYL CARBONATE: A NEW EFFICIENT COUPLING AGENT FOR THE DIRECT ESTERIFICATION OF CARBOXYLIC ACIDS
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Reaction of carboxylic acids with equimolar amounts of di-2-pyridyl carbonate and alcohols or thiols in the presence of 4-dimethylaminopyridine as a catalyst in methylene chloride at room temperature affords the corresponding esters in high yields under mild conditions.
- Kim, Sunggak,Lee, Jae In,Ko, Young Kwan
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p. 4943 - 4946
(2007/10/02)
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